‘I am afraid you will see the stain on my soul’: Direct gaze neural processing in individuals with PTSD after moral injury recall

Abstract Direct eye contact is essential to understanding others’ thoughts and feelings in social interactions. However, those with post-traumatic stress disorder (PTSD) and exposure to moral injury (MI) may exhibit altered theory-of-mind (ToM)/mentalizing processes and experience shame which precludes one’s capacity for direct eye contact. We investigated blood oxygenation level-dependent (BOLD) responses associated with direct vs averted gaze using a virtual reality paradigm in individuals with PTSD (n = 28) relative to healthy controls (n = 18) following recall of a MI vs a neutral memory. Associations between BOLD responses and clinical symptomatology were also assessed. After MI recall, individuals with PTSD showed greater activation in the right temporoparietal junction as compared to controls (T = 4.83; pFDR < 0.001; k = 237) during direct gaze. No significant activation occurred during direct gaze after neutral memory recall. Further, a significant positive correlation was found between feelings of distress and right medial superior frontal gyrus activation in individuals with PTSD (T = 5.03; pFDR = 0.049; k = 123). These findings suggest that direct gaze after MI recall prompts compensatory ToM/mentalizing processing. Implications for future interventions aimed at mitigating the effects of PTSD on social functioning are discussed.

Human eye contact provides a rich source of social and nonverbal communication, as it is integral to creating bonds with others.Specifically, direct eye gaze is distinguished from averted eye gaze in that it signals one's motivation to approach another (Ziaei et al., 2017) to, in turn, facilitate social cognitive processes known as 'theory of mind' (ToM) or 'mentalizing' (Conty et al., 2007).While mentalization helps individuals understand affective emotional states, ToM involves understanding the intentions and beliefs of others to navigate social interactions and engage in goal-directed behaviours (Frith and Frith, 2005).However, individuals with post-traumatic stress disorder (PTSD) often experience hypervigilance and alterations in arousal, which may create a bias toward perceived threat during direct eye contact (Krill and McKinnon, 2010;Wilkinson, 2010;Steuwe et al., 2014) and diminish capacities to engage in social situations.
The effect of PTSD and moral injury on direct eye gaze PTSD develops after experiencing a traumatic event(s) and is characterized by a sequela of symptoms (e.g.intrusive memories, hypervigilance) (American Psychiatric Association, 2013).
Traumatogenic symptomatology can also include pervasive feelings of shame and guilt, particularly for those who experience interpersonal trauma (Plante et al., 2022), which significantly hinder relationships (Budden, 2009;Dorahy, 2010;Dorahy et al., 2013;Cunningham, 2020) and may propagate feelings of isolation and disconnectedness from others (Lanius et al., 2011).Thus, the threat imposed by direct eye gaze can physically and emotionally dysregulate individuals with PTSD, disrupting their understanding of the emotions, intentions, and behaviours of others.Indeed, deficits have been reported in tasks measuring ToM/mentalizing performance for individuals with PTSD (Nazarov et al., 2014;McKinnon et al., 2016).
Deficits in social cognitive processing linked to direct eye gaze may be particularly relevant for those whose traumatic experience stems from a moral injury (MI) that was interpersonal in nature.MI refers to the experience of either perpetration of a moral violation and/or perceived moral betrayal by a trusted individual or organization in power (Shay, 2014;Schorr et al., 2018).Some examples include: experiences of abuse and/or neglect in childhood from a caregiver or trusted adult; being unable to help someone who is suffering (e.g.paramedics, firefighters); witnessing or killing another person in one's military role; or not receiving necessary support for mental health difficulties acquired from one's occupation.MI can foster a loss of confidence in one's own or others' ability to engage in ethical behaviours (Drescher et al., 2011) and is linked to general decline in positive affect and resilience (Wisco et al., 2017;Williamson et al., 2018;Griffin et al., 2019) and feelings of shame, rage and guilt (Litz et al., 2009;Dombo et al., 2013;Kopacz et al., 2015;McEwen et al., 2020;Brémault-Phillips et al., 2022) that may become particularly salient when experiencing direct eye contact.One client described the experience as: 'If somebody saw into my eyes and saw what I took part in….It feels, really scary.I feel like they're going to see a kind of stain on my soul' (Frewen and Lanius, 2015).Thus, direct eye contact becomes a vulnerable experience where the actions or inactions of traumatic experiences seem transparent to any person the individual encounters, suggesting that the experience of MI and associated feelings of shame can negatively distort how one views oneself in the world.Nevertheless, there is a dearth of research examining the associations between PTSD, MI and direct eye gaze.To our knowledge, no study has examined neural mechanisms of eye contact following a morally injurious event in individuals with interpersonal trauma-related PTSD.

Neural processing of direct eye gaze in healthy individuals
The core neural regions involved in social cognition in healthy individuals include specialized perceptual processing areas such as the extrastriate cortex ('body area') involved in the perception of biological or intentional motion and the fusiform gyrus ('face area') involved in perceiving facial expressions (Stevens and Jovanovic, 2018).Additionally, the dorsomedial prefrontal cortex (DMPFC) has been implicated in self-referential processing (Saxe et al., 2006;Schmitz and Johnson, 2007;Legrand and Ruby, 2009), which refers to how individuals relate to stimuli encountered in their environment (Northoff et al., 2006).The DMPFC works in tandem with the temporoparietal junction (TPJ) and the bilateral temporal poles to carry out neural processes integral to ToM/mentalizing such as recognizing emotional facial expressions, adopting the perspective of others and understanding the motivations, behaviours and thoughts of others (Van Overwalle, 2009;Carter and Huettel, 2013;Schurz et al., 2014).In particular, the TPJ is involved in processing transient social information whereas the DMPFC is involved in processing stable traits in others (Van Overwalle, 2009;Schurz et al., 2014).Furthermore, when processing the emotional states of others, the bilateral insula and the midcingulate cortex are involved in passive observation and active evaluation, respectively (Fan et al., 2011).The cerebellum has also been found to be significantly linked to ToM/mentalizing processes, such as 'person mentalizing' (e.g.ability to understand the traits, preferences and characteristics of people or oneself), 'event mentalizing' (e.g.understanding the intentions and beliefs behind the behaviours of others) and 'abstract mentalizing' (e.g.projecting oneself into the future and autobiographical recall) (Van Overwalle et al., 2014).While some activity supporting these processes has been reported in the right anterior lobules IV and VI, most mentalizing processing occurs in the posterior regions of the cerebellum (e.g.bilateral Crus I/II) (Van Overwalle et al., 2020).Indeed, a recent meta-analysis reported that 74% of the included studies showed significant associations between the posterior Crus II region and mentalizing and self-related emotional processing (Van Overwalle et al., 2020).Taken together, the cerebellum may also support the social cognitive processes involved in direct vs averted eye gaze.

Neural processing of direct eye gaze in individuals with PTSD
Compared to healthy controls, individuals with PTSD exhibit abnormal neural patterns during social cognitive processing (Frewen et al., 2010;Lanius et al., 2011;Steuwe et al., 2014;Thome et al., 2014;Rabellino et al., 2018).However, few studies have explicitly compared the neural correlates of direct vs averted eye gaze in individuals with PTSD vs healthy controls.Some have postulated that, in healthy individuals, direct eye gaze activates higher cortical structures supporting social cognitive processing such as the superior temporal sulcus, medial prefrontal and orbitofrontal cortices and fusiform gyrus (Liddell et al., 2004;Johnson, 2005) via pathways emanating from subcortical structures including the superior colliculus, periaqueductal grey, amygdala and thalamic pulvinar nuclei (Senju and Johnson, 2009;de Gelder et al., 2011).Steuwe et al. (2014) examined blood oxygenation leveldependent (BOLD) responses in female participants exposed to a male avatar displaying direct vs averted eye gaze and found that healthy individuals showed a response in the DMPFC, left TPJ and right temporal pole during direct eye gaze.However, PTSD participants demonstrated increased BOLD responses in subcortical structures such as the superior colliculus and the periaqueductal grey which, in addition to the locus coeruleus, amygdala and post-central gyrus, comprise the 'innate alarm system' (Liddell et al., 2005;Lanius et al., 2017).Activation of this system supports reflexive defensive responses to threat (Steuwe et al., 2014), and its chronic activation can limit higher-level cortical engagement of ToM processes (Thome et al., 2014).Another study examining the salience network during direct eye gaze in individuals with PTSD found increased within-network functional connectivity with the left amygdala and right insula for participants with PTSD as compared to healthy controls (Thome et al., 2014).While the salience network supports detection of and attention to external stimuli to inform behaviours aimed at maintaining cognitive, emotional and behavioural homeostasis (Craig, 2002;Seeley et al., 2007;Menon and Uddin, 2010), it can also contribute to PTSD symptoms such as hypervigilance (Hayes et al., 2012).Taken together, previous studies examining neural correlates of direct vs averted eye gaze support the possibility that direct eye gaze initiates activation of automatic, subcortical processes which may then modulate higher-order ToM/mentalizing processes.
As an extension of Terpou et al. (2022), we examined the neural correlates of direct eye gaze in civilians with interpersonal trauma-related PTSD as compared to healthy controls following recall of a morally injurious vs neutral memory during a virtual reality paradigm based on previous studies (e.g.Schrammel et al., 2009;Steuwe et al., 2014).Notably, we manipulated gaze interaction (i.e.direct vs averted), not emotional expression, based on the findings by Steuwe et al. (2014) that group differences were independent of the emotions displayed by facial expressions.We hypothesized that the PTSD group would show increased activation in the subcortical structures involved in the innate alarm system (e.g.superior colliculus, locus coeruleus, amygdala) and lower activation in cerebellar and higher-order cortical structures involved in ToM and self-referential processes (e.g.TPJ, DMPFC, bilateral temporal poles) (Liddell et al., 2004;Senju and Johnson, 2009;de Gelder et al., 2011;Van Overwalle et al., 2014).

Participants
Participants were recruited via advertisements within local mental health treatment centres and the community.The final sample consisted of forty-six participants including those with a primary PTSD diagnosis related to civilian trauma (N = 28) and MI event-exposed, healthy controls (N = 18).The group with a PTSD diagnosis was comprised of individuals with occupational or interpersonal-related PTSD as an extension of the analyses reported in Terpou et al. (2022).Demographics and clinical characteristics of the sample are presented in Table 1.
Exclusion criteria included a lifetime diagnosis of bipolar or psychotic disorder, alcohol or substance use disorder in the three months prior to study participation, noncompliance with 3 Tesla functional magnetic resonance imaging (fMRI) safety standards, pregnancy, head injury with loss of consciousness, a neurological or pervasive developmental disorder and significant untreated medical illness.Additionally, control participants were excluded if they had any history of psychiatric disorders and were screened using the Moral Injury Events Scale (MIES; Nash et al., 2013) to confirm exposure to potentially morally injurious events.
Approval was obtained for the study protocol via the Health Sciences Research Ethics Boards at Western University (#107575).Participants provided informed written consent prior to study involvement and were compensated $25 for the assessment interview and $50 for the MRI scanning visit.Participants recruited out of town were also reimbursed for travel expenses to London (e.g.mileage and parking).

Clinical interviews
Participants completed the Structured Clinical Interview for DSM-IV Axis-I Disorders-Research Version (First et al., 2002) to determine psychiatric history for study inclusion and determine comorbidities.The Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) (Weathers et al., 2013) was administered to evaluate PTSD symptom severity.Dissociative symptoms were assessed via the Multiscale Dissociation Inventory (MDI) (Briere et al., 2005) and child maltreatment and neglect were evaluated using the Childhood Trauma Questionnaire (CTQ) (Bernstein et al., 1994).Participants also completed the Interpersonal Reactivity Index (IRI) (Davis, 1980).The IRI evaluates perspective taking (i.e.ability to adopt the psychological point of view of others spontaneously), fantasy (i.e.ability to imaginatively experience the feelings and actions of fictitious characters in plays, books etc.), empathic concern (i.e.feelings of concern and sympathy for others) and personal distress (i.e.feelings of anxiety and unease in stressful interpersonal contexts).The Beck Depression Inventory-II (Beck et al., 1996) was administered to assess attitudes and symptoms of depression during the previous two weeks.Finally, participants also completed the 24-item Trauma-Related Shame Inventory (TRSI), which assesses internalized and externalized experiences of shame that are attributed to trauma (Oktedalen et al., 2014).
During the clinical assessment, participants were asked to describe a MI and neutral event that occurred within the same time period in eight sentences.They were provided with multiple MI definitions and discussed further with research staff to ensure the chosen events were appropriate (see supplementary materials for specific instructions) and reflective of 5-8/10 subjective units of distress to match distress intensity across groups.Following the procedure consistent with the Autobiographical Interview Administration Manual (Levine et al., 2002;McKinnon et al., 2015), recall was facilitated in a step-wise manner by reading and presenting the eight sentences in chronological order to the participant in the scanner.Self-report ratings of experienced shame, guilt and betrayal intensities as well as items related to dissociation and re-experiencing from the Responses to Script-Driven Imagery Scale (RSDI; Hopper et al., 2007) were collected after each script (See Table 2).

Experimental setup
Participants lying supine on the MR scanner bed were presented with their neutral memory script followed by their MI memory script with a 2-min break in between according to standard methods (Lloyd et al., 2021).The experimental paradigm was preceded and followed with resting-state scans of eight-minute duration for the purpose of future analyses.For each script, sentences were presented one by one.The first sentence was presented visually and simultaneously read aloud to the participant via MR compatible headphones in a neutral affective tone for 5 s.Next, participants spent 25 s recalling that part of their memory (detailed protocol is published elsewhere (Lloyd et al., 2021)).Following recall, the avatar protocol was presented and then the procedure was repeated for the next sentence (see Figure 1 below).E-Prime 3.0 software (Psychology Software Tools, Pittsburgh, PA) was used to present stimuli.An MR-compatible button press was used by participants after each script to rate the degree to which 1.1 (0.4) 3.2 (1.0) 1.2 (0.4) 3.4 (1.0) 1.3 (0.7) 3.4 (1.1) 1 (0) 2.3 (0.9) 1.1 (0.3) 2.8 (1.0) 1.00 (0) 1.6 (0.7) Note.Participants completed the Responses to Script-Driven Imagery Scale (RSDI) after each condition (neutral, moral injury (MI)) and rated how much they were experiencing feelings of shame, guilt and betrayal from 1 (Not at all) to 4 (Very much so).

Gaze paradigm: avatar protocol
Consistent with the stimuli and paradigm outlined by Schrammel et al. (2009), after the MI or the neutral event recall, video sequences were presented that involved an avatar moving across the screen and either turning directly to the participant or at a 30 ∘ left or right angle to indicate that the avatar may be looking at something or someone else (See Figure 2).Only male avatars were used as they received higher ratings on naturalness, dominance and sociability as per Schrammel et al. (2009).Each video sequence involved three epochs for a fixed interval of 8.93 s.
In the first epoch, the avatar enters the screen from the left or right (2.44 s).In the second epoch, the avatar then turns their head and body towards the participant indicative of mutual eyeto-eye contact (direct gaze) or at 30 ∘ (averted gaze) (4.05 s).In the final epoch, the avatar turned away and left the screen from the opposite side from where it entered (2.44 s).Eight 8.93 s video sequences were presented, each followed by a 5 s fixation cross.Immediately after the scanning session, participants completed the Tonic Immobility Scale (Forsyth et al., 2000).They were also shown still pictures of the avatar facial expressions and asked to identify the emotion the avatar was expressing as well how they felt in response to the avatar (e.g.shame, helplessness, sadness) presented in Table 3.

fMRI image acquisition
A 3 Tesla MRI Scanner (Biograph mMR; Siemens Medical Solutions) was used for brain imaging with a Siemens 32-channel head coil locally adapted to this scanner's 4-plug interface.We collected orthogonal scout images, which were used to prescribe a tri-dimensional T1-weighted anatomical image of the whole head with 1 mm isotropic resolution (Magnetization Prepared Rapid Gradient Echo).Functional whole-brain images with BOLD contrast were acquired transversely with the manufacturer's gradient echo, T2*-weighted blipped-echo-planar sequence (TE = 20 ms, TR = 3000 ms, FOV = 256 × 256 mm, flip angle = 90 ∘ , in-plane resolution = 2 × 2 mm), parallel imaging acceleration factor = 4).Each volume included 60 ascending interleaved slices with a thickness of 2 mm.We stabilized participants' heads with foam padding, and the experimental runs each consisted of 118 volumes.

fMRI pre-processing
Functional images were pre-processed using SPM12 (Welcome Trust Centre for Neuroimaging, London, UK: http://www.fil.ion.ucl.ac.uk/spm) within MATLAB R2019 (MathWorks Inc., MA).The pre-processing protocol involved discarding the four initial functional volumes, re-orientation to the anterior-posterior commissure axis, spatial alignment to the mean image using a rigid body transformation and re-slicing, and co-registration of the functional mean image to the subject's anatomical image.
Co-registered images were segmented using the 'New Segment' method in SPM12.Functional images were normalized to MNI space (Montréal Neurological Institute) and were smoothed with a full-width half maximum Gaussian kernel of 6 mm (Beissner et al., 2011).Additional correction for motion was implemented using the Artifact Removal Tool (ART) software package (Gabrieli Lab, McGovern Institute for Brain Research), which computes regressors that account for outlier volumes.

First-level analysis
All events (rest, instructions, fixation and conditions) were modelled as brain activation blocks combined with the hemodynamic response function for each participant.117 volumes were used, with one additional volume excluded because presentation of stimuli ended partway through its acquisition.At this stage, functional data were high-pass filtered, and serial correlations were accounted for using an autoregressive AR (1) model; ART software regressors were included as nuisance variables to account for any additional movement artifacts.The direct and averted eye gaze experimental conditions were modelled separately on the first level for each participant.

Second-level analysis
Contrast images for direct and averted gaze were entered into second-level analyses in SPM12 to examine between group differences in neural activation during direct gaze processing.First, a full factorial split plot analysis of variance was conducted to explore the interaction between participant group (PTSD, control), and condition (direct, avert) via a 2 (group) x 2 (condition) matrix.Group differences in neural activation were examined at the whole brain level for the two gaze and MI conditions with separate two-sample t-tests.Moreover, a region of interest (ROI) analysis was conducted to examine cerebellum activation in both the PTSD and control groups.For our ROI, we selected the Spatially Unbiased Infratentorial Template Toolbox (SUIT) mask (Diedrichsen, 2006).The SUIT template mask includes a high-resolution, MNI-normalized cropped cerebellum and brainstem.Given the large size of the mask, it can be considered a conservative selection as an ROI.We used voxel-wise thresholds set to P < 0.001 uncorrected.For between-group analyses, a conservative significance threshold was set to P < 0.05 FDR-corrected for cluster-level significance.Neural structures were confirmed via visual inspection using the neuromorphometrics atlas in SPM, AAL atlas and cross-referencing MNI coordinates with Brodmann's areas.

Demographics and clinical measures
As expected, the PTSD group scored significantly higher for CAPS-5 total score (and subscales), MDI, CTQ, IRI-PD, TRSI, BDI and MIES as compared to the control group.Also, while we found a significant difference between groups for age, upon closer examination of the influence of age on the BOLD signal yielded non-significant differences across conditions.No significant differences were found between groups for sex.

Discussion
The current study sought to identify the neural correlates of direct eye gaze (vs avert) in participants with PTSD as compared to healthy controls following recall of a MI or neutral memory.Our findings revealed that following recall of a morally injurious memory, but not a neutral memory, the PTSD group showed greater activation in the TPJ as compared to controls, an area central to multisensory processing and ToM/mentalizing processes (e.g.self-reflection, perspective taking) (Van Overwalle, 2009;Carter and Huettel, 2013;Schurz et al., 2014).Further, those with PTSD demonstrated a significant positive association between right MSFG activation and experiences of personal distress in stressful interpersonal situations, as well as a negative association between  cerebellum crus II activation and higher levels of trauma-related shame following recall of the MI memory.These findings may suggest that there are compensatory efforts by higher-order cortical structures to support one's evaluation of the nature of the direct eye gaze following recall of a morally injurious event.Moreover, theorized top-down modulation may be enhanced when experiencing anxiety within the social context that direct eye gaze creates.Conversely, bottom-up ToM/mentalizing processes supported by the cerebellum may be disrupted by experiences of shame particularly within the context of recalling a MI.Taken together, these findings suggest an alteration in ToM/mentalizing processes of individuals with PTSD after MI, but not neutral, memory exposure during direct eye gaze processing.

Neural correlates of direct gaze in the PTSD group
Increased activation of the TPJ in the PTSD group (as compared to controls) during direct gaze after recalling a MI, but not neutral memory, suggests that they may attempt to engage their altered ToM/mentalizing skills when faced with the direct gaze of the avatar.Notably, these findings were not aligned with the initial study hypothesis that direct eye gaze would show activation restricted to the automatic 'innate alarm' subcortical network in the PTSD group (e.g.superior colliculus/periaqueductal grey), which would limit engagement of higher-order cortical structures implicated in social cognitive processes (e.g.TPJ, medial prefrontal and orbitofrontal cortices) (Liddell et al., 2004;Johnson, 2005;Senju and Johnson, 2009).These results contrast with the findings by (Steuwe, et al., 2014)of diminished ToM-related cortical engagement in PTSD during direct gaze.One notable difference in the current study was our inclusion of a personalized MI-event script presented to participants prior to the avatar displaying direct or averted eye gaze.Participants chose events that would elicit a mid-to-high range moral emotion response (e.g.shame).It is possible that this methodological difference resulted in activation of the innate alarm system during MI recall which was then overcome by top-down modulation when the avatar was displayed.Consistent with this postulation, our colleagues found that during script-driven MI event-related memory recall, participants with PTSD showed increased activation both in subcortical areas of defensive responding (e.g.innate alarm system) and in cortical regions involved in modulation (e.g.dorsolateral prefrontal cortex) (Lloyd et al., 2021).
Importantly, there were no significant differences between the PTSD and control groups during direct (vs avert) gaze when recalling a neutral event, which suggests that these neural response patterns may be unique to morally injurious events; similar findings exist in related studies (Lloyd et al., 2021;Terpou et al., 2022).Exposure to a MI can elicit emotions that may result in a wider distribution of activity across neural regions responsible for social cognition among others (e.g.moral reasoning, emotion regulation) (Bryan et al., 2018).Though speculative, there may be competition in activation between the subcortical and cortical neural regions subsequent to the MI memory recall task when the participant is exposed to direct eye gaze (via the avatar).Furthermore, given that direct eye gaze can capture and hold attention (Senju and Hasegawa, 2005), the avatar may have required increased use of attentional processes that involve activation in higher-order cortical areas overlapping with those involved in ToM/mentalizing.As direct gaze increases autonomic arousal (Hietanen et al., 2008;Helminen et al., 2011), it may be possible that participants experienced heightened arousal corresponding with activation of the innate alarm system, but then suppressed it through heightened convergent activation in cortical structures from both attentional and ToM/mentalizing neural processes.Future research should consider measuring physiological arousal in addition to fMRI to determine whether individuals with MI-related PTSD suppress/over modulate the innate alarm system.
Interestingly, the use of the virtual characters-as opposed to a 'live' person-in the current study has been utilized previously (Schrammel et al., 2009;Steuwe et al., 2014;Thome et al., 2014) and studies have demonstrated differences in neural activation in participants presented with a robot with a biological appearance (or virtual character) as compared to a robot without biological appearance or a human (Saygin et al., 2011).It is possible that the participant perceives a virtual character as unpredictable, resulting in activation of subcortical structures to initiate a defensive response (e.g.innate alarm system) (Steuwe et al., 2014).However, it is also possible that, while still threatening, the virtual character additionally elicits an evaluative, reflective response from participants given the knowledge that the character is not real.This supports the observed TPJ activation given its involvement in processing transient social cues.Future studies should aim to explore potential differences in the neural activation patterns of individuals with and without PTSD when presented with direct eye gaze from a virtual vs live person.

Neural correlates of personal distress and trauma-related shame
Among individuals with PTSD exposed to a MI, direct eye contact was linked to greater activation in the right MSFG with increasing scores on the IRI-PD, which translate to higher anxiety and discomfort in social contexts.MSFG has been linked to self-reflective processes such as self-evaluation and self-judgment and processing negative self-related emotions, such as shame (Goldberg et al., 2006;Thome et al., 2014;Frewen et al., 2020).Further, higher IRI-PD scores have been reported in other samples of individuals with PTSD (Parlar et al., 2014) and can behaviourally manifest as fearfulness, social dysfunction and emotional vulnerability (Davis, 1983).Indeed, one client noted: 'To make any kind of eye contact was to bring attention to myself, and it would be met 99% of the time with being slugged or hit in some way…I learned not to make eye contact, not to move, not to speak, and not to do anything.I learned: "keep your eyes down all the time"' (Frewen and Lanius, 2015).Thus, those with traumatic and morally injurious experiences may avoid direct eye contact to defend against a perceived potential threat and subsequent emotional dysregulation.It is also possible that individuals with PTSD experiencing heightened anxiety can struggle to evaluate their role in a social interaction and process associated trauma-related emotions.The positive association between personal distress and MSFG activation may be indicative of an effort to compensate for a disruption in self-referential and emotional processing.Indeed, activity in the frontal cortex in response to eye contact aids in attentional and mentalizing processes to evaluate the other person's intention and generate a planned behavioural response (Halgren and Marinkovic, 1995;Panksepp, 1998;Liddell et al., 2004).The ambiguity of direct eye contact from a neutral expression on the avatars may exacerbate this compensatory effort given the amount of processing required to evaluate the context (Neta and Whalen, 2010).Indeed, individuals tend to perceive neutral stimuli negatively (Said et al., 2011), and this may be especially true for individuals with PTSD who tend to have an enhanced sensitivity for detecting potential threat (Krill and McKinnon, 2010;Wilkinson, 2010;Aupperle et al., 2012).Notably, this was partially captured in the PTSD group participants' ratings of their emotions in response to the avatars.Participants in the control and PTSD groups were both shown still images of avatars with neutral facial expressions with direct and averted eye gaze and asked to rate how they felt from 1 ([emotion] not present) to 9 ([emotion] extremely [present]).For all of the possible feelings (i.e.shame, guilt, betrayal, helplessness, anger, sadness), the control group consistently reported not experiencing any of the emotions after presentation of each avatar (i.e.mean range = 1.00 to 1.06).However, the ratings were slightly more variable for the PTSD group with the highest mean rating reaching 3.40 (SD = 3.12) for sadness (see Table 3).This slight variability in the PTSD group ratings provides support for the possibility that the neutral expression of the avatar provided ambiguity that participants tended to perceive more negatively than the control group.
The ROI analysis also demonstrated significant associations between lower activation in the left cerebellum crus II and higher scores on the shame inventory suggesting that the experience of shame may disrupt crus II-mediated social cognitive processes.Indeed, childhood trauma, for example, is significantly linked to maladaptive self-processes including shame and self-criticism which can have cascading adverse effects on individuals' quality of life and relationship satisfaction (Menke et al., 2018).Numerous studies have revealed the distinct role of crus II in ToM/mentalizing processes (Van Overwalle et al., 2020), such as intuitively understanding human actions to promote adaptations to novel situations (Heleven et al., 2019;Van Overwalle et al., 2019) and considering the potential responses of others when guiding goaloriented behaviour (Van Overwalle and Mariën, 2016;Heleven et al., 2019).The intense experience of shame that is commonly associated with PTSD (Saraiya and Lopez-Castro, 2016) and MI (Litz et al., 2009;Dombo et al., 2013;Kopacz et al., 2015;McEwen et al., 2020) can lead to a profound experience of powerlessness and lack of self-worth (Muris and Meesters, 2014), which may prompt individuals to engage in defensive and avoidant behaviours with the desire to hide or escape from the world.Indeed, according to the results of the RSDI scale, 53.6% of participants in the PTSD group reported experiencing the highest rating of shame (i.e.'Very Much So') after exposure to the MI condition as compared to 6.3% of the control group.Further, none of the participants in the PTSD or control groups reported experiencing feelings of shame after the neutral condition (see Table 2).This adds to extant evidence that individuals with PTSD exposed to MI can elicit strong feelings of shame, which, when coupled with the direct eye gaze, can be overwhelming thus disrupting individuals' ability to interpret the novel social situation effectively.While neuroimaging studies have revealed connections between the posterior cerebellum and cortical structures central to ToM/mentalizing processes, such as the TPJ, in healthy individuals (Van Overwalle et al., 2015, 2019), future studies should examine these connectivity patterns during gaze processing in PTSD following MI recall.

Limitations and future directions
Despite the strengths of the study, there are a number of limitations that warrant consideration.First, group sample sizes were small due to the unexpected discontinuation of recruitment with the onset of the Coronavirus disease (COVID-19) pandemic.Future replication of the study with larger samples is needed to confirm the reliability of the findings.Second, we did not distinguish between individuals who met diagnostic criteria for PTSD and those with the PTSD dissociative subtype.Such comparisons may have yielded notable differences in results, as individuals of the dissociative subtype may exhibit over-modulation of higherorder cortical structures manifesting behaviourally as physical and emotional 'numbing' (Lanius et al., 2010;Harricharan et al., 2016;Nicholson et al., 2017;Schiavone et al., 2018).Third, our PTSD participants exhibited heterogeneity with regard to trauma histories.While this permits generalizability of the results to the broader population, it could have influenced the salience of neural activation patterns since social cognitive processing may vary depending on the type, onset and duration of the trauma experienced (Nazarov et al., 2014).Relatedly, we did not capture the frequency of exposure to morally injurious events which could have also influenced the current study results.Future studies should focus on comparisons across different etiological profiles of trauma and/or MI to further elucidate the patterns of neural activity during eye gaze processing.Further, as we did not explore the effects of MI independently of PTSD diagnosis, future research may also aim to examine the potential unique effects of MI on direct (vs avert) gaze neural processing.Finally, as we only explored activation of neural structures, future studies should conduct network analyses to explore changes in connectivity during exposure to direct vs avert gaze post MI event recall.

Conclusion
Our results demonstrate that social cognitive processing measured during the experience of direct eye gaze after MI recall is altered in individuals with PTSD as compared to healthy controls.These findings reveal that direct eye gaze may instigate compensatory processing in individuals with PTSD, particularly after exposure to a MI event.Significant alterations in the social cognitive processes of individuals with PTSD (e.g.TPJ, right MSFG, left cerebellum crus II) when met with direct eye gaze can have adverse implications for their ability to develop and maintain healthy relationships.The current findings may be useful in informing future interventions aimed at mitigating the effects of PTSD on individuals' social cognitive functioning.

Fig. 2 .
Fig. 2. Avatar direct and averted eye gaze presented to the participant on the screen in the scanner following moral and neutral memory recall.

Fig. 3 .
Fig. 3. Activation in the right temporoparietal junction in the PTSD group as compared to the control group.

Fig. 4 .
Fig. 4. Significant positive correlation between scores of IRI-PD and activation in the right medial superior frontal gyrus in PTSD group.

Fig. 5 .
Fig. 5. Significant negative correlation between scores of the TRSI and activation in the left cerebellum crus II in PTSD group via ROI analysis.

Table 2 .
Participant responses to the Script-Driven Imagery Scale after the moral injury and neutral conditions

Table 3 .
Means and standard deviations of participant ratings of their emotions in response to the avatars displaying neutral affect